Typically, twisted nematic (TN) mode or super twisted nematic (STN) mode is employed in LCDs. Unfortunately, TN mode and STN mode LCDs are disadvantageous for their narrow viewing angles. IPS LCD is therefore proposed for wider viewing angle. In addition to the wider viewing angle, an IPS LCD has the advantages of no compensator and fast response, and furthermore, there is one mask less than the TN mode LCD for its manufacture. However, the pixel electrode and the counter electrode of an IPS LCD are made of opaque metal and thus have smooth surfaces, resulting in mirror reflection and lower contrast. Even a rough surface made of organic material such as resin can be formed underlying the pixel electrode and the counter electrode to improve this weakness, introduction of additional organic material requires more masks in the manufacture process and thus increases process complexity and cost. Furthermore, the thermal durability of the organic material is not good for it is up to only about 250° C. On the other hand, the large difference between the higher and the lower levels of the rough surface as of 0.5–1.5 um forces the LCD to have its cell gaps being enormously varied, resulting in the reflection efficiency lowered from ideally 100% to 60–85%.
Therefore, it is desired an IPS LCD with improved rough surface for the reflector thereof and decreased number of mask in its manufacture process.